<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<style type="text/css">
		
			*{
				margin: 0;
				padding: 0;
			}
			
			.father{
				width: 300px;
				height: 300px;
				background: pink;
				border: 10px solid black;
				overflow: hidden;  /*当子类设置了margin-top的时候 我们需要给父类设置overflow:hidden;*/
				margin: 0 auto;
			}
			
			.one{
				width: 100px;
				height: 100px;
				background: red;
				margin-left: 200px;
			}
			
			.two{
				width: 100px;
				height: 100px;
				background: green;
				margin-left: 100px;
			}
			
			.three{
				width: 100px;
				height: 100px;
				background: blue;
				margin-left: 200px;
			}
		</style>
	</head>
	<body>
		<div class="father">
			<div class="one"></div>
			<div class="two"></div>
			<div class="three"></div>			
		</div>		
	</body>
</html>
